The present invention relates to a device for the minimal-invasive removal of tissue from animal or human tissue, which device has a hollow needle provided with a hollow channel.
There are numerous known different methods and devices employed to examine tissue for the selective removal of tissue from animal or human bodies. Starting with the familiar classical surgical procedure using a scalpel to provide a passage to the to-be-severed and to-be-examined tissue area in order to sever this tissue area with selective cuts and to remove it from the body through the work passage, one proceeded, due to the many drawbacks related to this classical surgical procedure, to design a suited instrument for minimal-invasive surgery. Although, it is possible to extract sufficiently large amounts of tissue material from the body for examination with the classical method, the surgery and the related tissue sections involve irreversible tissue irritation, which takes much time to heal. Moreover, there is the danger of cell displacement in that tissue that may be tumorous is severed and removed through the work passage is carried to nonmalignant tissue.
In order to rule out the drawbacks described above, punch biopsy devices are known which permit removing tissue at selected intracorporal tissue areas by means of a single incision with a needle. This comprises a combination of a hollow needle having a mandrel running inside the hollow needle. This mandrel is provided with a recess at the distal end in which tissue, that can be severed with the aid of the sharpened distal end of the hollow needle, can be stored. Although this type of tissue removal is minimal-invasive and involves only minor tissue irritation caused by the injection of the needle arrangement into the body and the needle arrangement largely rules out the problem of cell displacement because the tissue severed in the to-be-examined tissue is enclosed in order to be safely removed from the body. The disadvantage of the known punch biopsy, however, is that only a small amount of tissue can be removed with a single incision of the hollow needle. Although the amount of the to-be-examined tissue can be increased by multiple successive biopsies, the tissue is greatly stressed and irritated by the numerous incisions. On the other hand, hollow needle arrangements with increasingly larger cross sections can be resorted to, however, this raises the danger of bleeding and consequently hematoma formation leading to unavoidable side effects.
The object of the present invention is to design a device for minimal-invasive removal of tissue from animal or human tissue, which device has a hollow needle provided with a hollow channel, in such a manner that the afore-described drawbacks can largely be prevented. In particular, the aim is to reduce to a minimum irreversible tissue irritation caused by the surgical operation by means of a minimal-invasive surgical procedure in the to-be-examined tissue area. Injury to the tissue cells from the surgical procedure should also be minimized and the danger of bleeding should be reduced to a minimum. Despite the minimal-invasive surgical procedure, it should still be possible to remove from inside the body a minimum amount of tissue material required for unequivocal determination of the tissue respectively examination of the tissue.
The solution to the object of the present invention is given in claim 1. Advantageous features that further develop the inventive idea are the subject matter of the subclaims and are disclosed in the description as well as in the preferred embodiment with reference to the accompanying drawing.
An element of the present invention is to design a device for minimal-invasive removal of tissue from animal or human tissue, which has a hollow needle provided with a hollow channel, in such a manner that the hollow needle is designed as a multi-wall hollow needle and is provided with at least two hollow needle walls enclosing at least one intermediate space which is designed open at the distal end. Extending at the distal end from this intermediate space is a cutting wire that can be supplied with electric energy and is preferably designed with a shape corresponding to the contour of the cross section of the intermediate space and is located at a distance opposite this intermediate space. A supply line for a material flow ends in the proximal end of the intermediate space of the multi-wall hollow needle, with the supply line and the intermediate space being connected and designed in such a manner that that the material flow flows through the intermediate space and exits at the distal end. Preferably an electrically nonconductive scavenging fluid, for example a glycol solution, is employed as the material flow. Moreover, the scavenging fluid should possess approximately the same mineral content as the human or animal tissue fluid or at least be chemically inert so that the intracorporal scavenging has no negative influence on the mineral content of the surrounding tissue.
Gases, for instance inert gases such as argon can also be used. Finally a vacuum source can be connected at the proximal end of the hollow channel of the preferably double-walled multi-wall hollow needle.
The multi-wall hollow needle preferably designed as a double-walled hollow cylinder is preferably provided with an exterior contour matching the interior contour of a hollow channel designed as a sluice serving as the work channel for intracorporal insertion of endosurgical instruments into the body, thus also for insertion of the invented hollow needle. To keep tissue and cell irritation to a minimum when inserting such a type of sluice, for example, through the various layers of the skin down to the to-be-examined tissue area, there are known sluice arrangements which are provided with a helical screw thread on their exterior and a tapering-to-a-tip screw thread at the distal end, with the screw tip being the distal end part of a mandrel extending through the sluice, which is led through for the purpose of entering the sluice arrangement inside the body. Such a type of sluice arrangement is described in DE 199 35 976.8. The particular advantage of such a type of sluice arrangement is that the tissue is not cut when the sluice arrangement is inserted, but rather is dilated by the spiral-like designed tip so that natural interfaces in the tissue respectively in the cell structures entered by the distal screw tip give way thus permitting to largely avoid severing blood vessels, nerves or cells. Positioning such a sluice can be controlled using ultrasonic, X-ray or MR monitoring methods to check the position relative to the to-be-examined tissue area.
If the sluice arrangement is positioned accordingly and the central mandrel is removed from the hollow channel, a work channel is created through which the invented tissue removal device can be placed accordingly. Fundamentally, leading the invented tissue removal device described in the following through other work channels or the work channel can even be completely obviated. This however is connected with distinct drawbacks during the surgical operation. For selective tissue removal, the multi-wall hollow needle is preferably double walled and designed as a hollow cylinder whose needle length is selected larger than the length of the sluice so that the multi-wall hollow needle extends out of the sluice at the distal end and can enter the to-be-examined tissue area accordingly. Entry of the distal end of the multi-wall hollow needle occurring into the tissue area is distinguished, in particular, by the cutting wire, which is disposed immediately before the open distal end of the intermediate space of the multi-wall hollow needle and whose shape essentially corresponds to that of the cross section of the intermediate space and is positioned at a slight distance therefrom, having electric energy, preferably HF current, applied to it and being heated thereby. The tissue coming into contact with the cutting wire is thermally severed and simultaneously a coagulation process sets in which prevents later bleeding. So to say the purpose of the cutting wire is a sort of high-frequency surgical cutting device which immediately protects the cell tissues from bleeding further during severing by means of thermal coagulation. Severing of the to-be-severed tissue can also occur by means of an erosion method, i.e. the tissue does not come into immediate contact with the cutting wire but rather is thermally denatured by the sparks discharged by the high electric voltages at the cutting wire. The sparks cause a plasma to form which leads to the desired erosion effects. Also feasible is a three-walled design of the multi-wall hollow needle, which contains two intermediate spaces, through one of which a scavenging fluid is led and through the other of which a gas is led at the distal end, which contributes to the selective plasma formation.
As a result of the distal advancing of the multi-wall hollow needle, the cutting wire, which is preferably designed like a sort of full circle, severs a tissue volume and conveys it into the hollow needle, which has the shape of a full cylinder. In order for the tissue severed from the other tissue to be able to completely enter into the interior of the multi-wall hollow needle, the hollow channel of the multi-wall hollow needle is connected to a vacuum source, by means of which all severed tissue areas are able to enter the interior of the multi-wall hollow needle. Moreover, a material flow, preferably a glycol solution, which is supplied to the hollow needle at the proximal end via a supply line exits from the distal end of the intermediate space. The glycol solution is able to considerably support the severing process and removal of the severed tissue areas into the inside of the hollow channel. Furthermore, the glycol solution ensures the desired cooling of the tissue surrounding the heated cutting wire, whereby minimizing the heat input on the surrounding tissue is minimized.
In addition to the circular design of the cutting wire, it is provided with a cutting wire bridge which is directed to the middle of the hollow channel surrounded by the multi-wall designed hollow needle. When inserting the cutting wire ring attached to the distal end of the multi-wall hollow needle into the tissue, the tissue is cut open by the cutting wire bridge in longitudinal direction to the severed tissue cylinder at least half of the severed cylinder diameter. If a desired incision depth is reached inside the tissue by corresponding insertion of the multi-wall hollow needle into the tissue area, the multi-wall hollow needle including the cutting wire arrangement is turned about the longitudinal axis of the hollow needle. As a result, the cutting wire bridge severs the tissue core located inside the multi-wall hollow needle completely on the distal side from the remaining tissue. The tissue sample severed from the remaining tissue inside the body in this manner is kept inside the hollow channel by means of the vacuum and can be easily removed from inside the body through the work channel of the sluice.
In order for the tissue sample completely severed inside the body not to be uncontrollably sucked away at the proximal end by the vacuum inside of the hollow channel of the multi-wall hollow needle, the vacuum source is connected to a single-walled hollow needle at whose distal end a meshwork or a similarly designed arrangement is provided so that only predominantly fluid parts or gas parts can be aspired through the hollow needle at the distal end of the single-walled hollow needle and severed solid material parts such as the tissue sample itself are kept in front of the hollow needle at the distal end by the meshwork. For this purpose, during the cutting process, the hollow needle is inserted at the proximal end into the hollow channel of the double-walled multi-wall hollow needle. The depth of entry of the single-walled hollow needle into the double-walled multi-wall hollow needle is selected in such a manner that there is sufficient distance between the distal end of the double-walled multi-wall hollow needle and the distal end of the single-walled hollow needle connected to the vacuum source so that a sufficient amount of tissue material can be drawn inside the hollow channel. In order to avoid cell displacement through healthy tissue areas, it is advantageous if the reception volume of the hollow channel of the double-walled multi-wall hollow needle is larger than the actual removed tissue volume. The vacuum inside the hollow channel holds the removed sample of tissue fast on the single-walled hollow needle thereby permitting removal of the single-walled hollow needle with the tissue core located at the distal end of the hollow needle.
If a second removal of tissue is required at another site in the tissue, renewed removal can be carried out using the thermal cutting device by changing the angle of the sluice.
If one replaces the sluice, which as previously described is designed with an exterior screw thread, with a hollow needle which is provided with a recess at the distal end, for example in the form of a cut out section extending halfway to the axis of the hollow channel, repeated tissue removal in the radial surrounding of the hollow needle is possible without moving the sluice respectively the work channel, thereby permitting further reduction of possible irritations. This occurs in such a manner that the multi-wall hollow needle is pushed into the suitable prepared hollow needle maximally to the proximal edge of the cut out section. A vacuum applied inside the multi-wall hollow needle ensures that the tissue material, which lies radially adjacent to the distal end of the hollow needle immediately opposite the cut out section, is drawn laterally into the hollow needle. Subsequently the multi-wall hollow needle is pushed toward the distal end with the heated cutting wire and the tissue material drawn into the cut out section is severed and is conveyed outside the body by means of the previously described method. This tissue severing procedure can be repeated accordingly after the hollow needle is slightly turned about its longitudinal axis. Turning the hollow needle occurs without any tissue irritation.
With the afore-described method, large pieces of tissue volume can be removed from the body piecemeal. The removal procedure occurs preferably under visual monitoring, for example by means of X-ray observation, so that selected tissue areas about the hollow needle arrangement can be removed in a minimal invasive manner.
In order to supply the cutting wire emerging from the distal end of the double-walled hollow channel with electric energy, the cutting wire is connected via an electric connection running at the proximal end inside the intermediate space. The electric connection runs at the proximal end via the supply line through which the intermediate space is supplied with glycol solution. As both the scavenging fluid and the electric lead run through one and the same intermediate space, it is absolutely necessary that the scavenging fluid is not electrically conductive. Corresponding variation of the cutting current, which is supplied to the cutting wire like a HF current, permits selective coagulation at the cutting site, which denatures the tissue and in this way prevents later bleeding as well as cell displacement.
After successful removal of tissue, the sluice acting as the work channel can be removed. The essentially dilated tissue assumes its original position again and can quickly heal.
A particular advantage for subsequent tissue analysis is the partial longitudinal section inside the tissue sample, severed as a full cylinder, due to the cutting-wire bridge, because the longitudinal section permits as a marking aid later unequivocal allocation to the original location in the to-be-examined tissue area before cutting.